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The idea that, in face of unchanged conditions, Natural 
Selection is necessary to produce the stability of species, is 
not only unnecessary, it is also contrary to experience. 
The carp remains unmodified, or, in other words, the 
stability of the species is maintained in the absence of 
selection ; and yet we are asked to believe that in nature 
the presence of Natural Selection produces the stability of 
species. Thus the same result is supposed to take place 
from diametrically opposite causes. This apparent in 
consistency can only be removed by distinguishing between 
two very different results : the mere maintenance of the 
stability of species, which we have seen does not exclude 
a great amount of individual variety, and the preservation 
of a species at the highest conceivable point of a typical 
excellence. Let us see what proof there is that Natural 
Selection has produced either of these results. 
The arguments already adduced serve to show that the 
stability of species can be maintained apart from Natural 
Selection, and that therefore we need not in this case 
invoke the principle of selection to do what the regression 
to mediocrity is perfectly competent to accomplish 
unaided. 
The principle of regression to mediocrity is clearly an 
tagonistic to any permanent modification of structure ; and 
when an organism is already adapted to new conditions, it 
is sufficient to maintain the correlation. Other principles 
which might be required to transmute a species will not be 
required to preserve its stability. The cessation of Natural 
Selection, supposing that principle had been on the field 
previously, would simply leave the law of variation and 
the law of regression to mediocrity to balance one another. 
We now come to the hypothesis that Natural Selection 
has been at work to maintain the species at the highest 
realisation of its perfect adaptation. What evidence can